readr::read_csv is misreading some column types in a file I am loading so I want to use cols to set them manually.
In ?read_csv, it says the col_types argument should be _"One of ‘NULL’, a ‘cols()’ specification, or a string. See ‘vignette("column-types")’ for more details". Well, vignette("column-types") gives vignette("column-types") not found so I tried ?cols. It says it accepts "column objects created by ‘col_*()’ or their abbreviated character names".
What are the acceptable functions or abbreviated character names and where do I find that information? readr 1.1.1 btw.
There are col_double, col_integer, col_character, col_date, col_factor, .etc
library(readr)
mtcars <- read_csv(readr_example("mtcars.csv"), col_types =
cols(
mpg = col_double(),
cyl = col_integer(),
disp = col_double(),
hp = col_integer(),
drat = col_double(),
vs = col_integer(),
wt = col_double(),
qsec = col_double(),
am = col_integer(),
gear = col_integer(),
carb = col_integer()
)
)
mtcars
#> # A tibble: 32 x 11
#> mpg cyl disp hp drat wt qsec vs am gear carb
#> <dbl> <int> <dbl> <int> <dbl> <dbl> <dbl> <int> <int> <int> <int>
#> 1 21 6 160 110 3.9 2.62 16.5 0 1 4 4
#> 2 21 6 160 110 3.9 2.88 17.0 0 1 4 4
#> 3 22.8 4 108 93 3.85 2.32 18.6 1 1 4 1
#> 4 21.4 6 258 110 3.08 3.22 19.4 1 0 3 1
#> 5 18.7 8 360 175 3.15 3.44 17.0 0 0 3 2
#> 6 18.1 6 225 105 2.76 3.46 20.2 1 0 3 1
#> 7 14.3 8 360 245 3.21 3.57 15.8 0 0 3 4
#> 8 24.4 4 147. 62 3.69 3.19 20 1 0 4 2
#> 9 22.8 4 141. 95 3.92 3.15 22.9 1 0 4 2
#> 10 19.2 6 168. 123 3.92 3.44 18.3 1 0 4 4
#> # ... with 22 more rows
Alternatively, you can use a compact string representation where each character represents one column:
c = character, i = integer, n = number, d = double, l = logical, D = date, T = date time, t = time, ? = guess, or _/- to skip the column.
mtcars_select <- read_csv(readr_example("mtcars.csv"),
col_types = cols_only(mpg = 'd', cyl = 'i', hp = 'i',
qsec = 'd', gear = 'i'),
na = c("NA", "N/A", "-9999", "-999"))
mtcars_select
#> # A tibble: 32 x 5
#> mpg cyl hp qsec gear
#> <dbl> <int> <int> <dbl> <int>
#> 1 21 6 110 16.5 4
#> 2 21 6 110 17.0 4
#> 3 22.8 4 93 18.6 4
#> 4 21.4 6 110 19.4 3
#> 5 18.7 8 175 17.0 3
#> 6 18.1 6 105 20.2 3
#> 7 14.3 8 245 15.8 3
#> 8 24.4 4 62 20 4
#> 9 22.8 4 95 22.9 4
#> 10 19.2 6 123 18.3 4
#> # ... with 22 more rows
Or even shorter
mtcars <- read_csv(readr_example("mtcars.csv"), col_types = "di_i__d__i_")
mtcars
# A tibble: 32 x 5
mpg cyl hp qsec gear
<dbl> <int> <int> <dbl> <int>
1 21 6 110 16.5 4
2 21 6 110 17.0 4
3 22.8 4 93 18.6 4
4 21.4 6 110 19.4 3
5 18.7 8 175 17.0 3
6 18.1 6 105 20.2 3
7 14.3 8 245 15.8 3
8 24.4 4 62 20 4
9 22.8 4 95 22.9 4
10 19.2 6 123 18.3 4
# ... with 22 more rows
Ref:
https://cran.r-project.org/web/packages/readr/vignettes/readr.html
https://www.rdocumentation.org/packages/readr/versions/1.1.1/topics/cols